临近地铁深大基坑支护技术的探析

On supporting technology for deep and large foundation pit near metro

地铁隧道内设备众多,空间狭窄,列车运行速度快,对地铁线路的变形有严格要求.当地铁周边有深大基坑工程时,必然会引起地铁隧道、车站产生不均匀沉降和水平位移,从而对地铁正常运营产生影响.以紧临深圳地铁2号线的某基坑工程为例,在基坑设计中,为了避免基坑开挖对临近地铁的正常运行产生影响,开展了变形影响因素分析,确定了关键风险点,采取了有针对性的支护结构型式与施工开挖方法.设计计算与施工监测结果表明:临近的地铁线路、车站的变形控制值均在规范允许范围内.

Numerous equipments in metro tunnel,narrow space and high speed of the train call for strict requirement of railway deformation.Deep and large foundation pit near metro brings about differential settlement and horizontal displacement of metro tunnel and station,which exerts an influence on normal operation of metro.Taking some foundation pit near metro line 2of Shenzhen as an example,we carry out analysis on influence factors of deformation during foundation pit design,determines key risk points of this foundation pit engineering,and adopts specific type of support structure and excavation method in order to avoid influence of excavation of foundation pit on normal operation of adjacent metro.Results of design calculation and construction monitoring show that deformation control value of adjacent metro railway and station is within the limit of allowed value.